The present invention is directed to applications where products such as printed circuit boards are moved from station to station during a manufacturing process. In particular, the invention relates to an apparatus used during electroplating to prevent drag-out.
In the manufacture of integrated circuit boards, the different components need to be plated with various materials. The plating is typically accomplished by electroplating. Electroplating requires that the components be transferred from one treating solution to another. The various treating solutions are contained in plating chambers. The circuit boards move from chamber to chamber in a continuous process. The treating solutions consist of various chemicals and are used to coat the workpiece with the desired materials. Each chemical bath may have a rinse bath after it and preceding the next chamber. Additionally, at the end of the electroplating process, the workpiece is usually removed from the final treating solution and rinsed in a water bath.
As the circuit board or workpiece is transferred from plating chamber to plating chamber, some of the solution in which the circuit board has been immersed adheres to the surface of the circuit board. In most instances, the adhering solution must be removed from the circuit board before it enters the next step in the process. When the boards are removed from the different plating chambers, the solution that adheres to the boards is called drag-out.
Drag-out has several detrimental effects. The solution adhering to the workpiece as it exits one plating chamber will be mixed with the treating solution in the subsequent plating chamber, potentially contaminating the solution therein. This contamination contributes to the solutions needing to be changed more frequently, increasing the cost and time involved in the process. Additionally, precious metals, such as gold, are sometimes plated onto the components of the circuit board. In order to make the electroplating process economically viable, as much of the precious metal as possible must be recovered when the panel leaves the plating solution. Moreover, if the rinse water used at the end of the plating process becomes contaminated with environmentally hazardous materials, the cost of cleaning and disposing of the rinse water substantially increases.
Therefore, there is a need for an apparatus which prevents drag-out between adjacent plating chambers. Reduced drag-out results in longer bath life from less contamination as well as an improvement in the yield of any precious metal used in the electroplating process.
The present invention provides an apparatus for preventing drag-out. The apparatus comprises at least one brush member which is adjustably arranged in a housing. One end of the brush member extends from the housing and contacts the workpiece as it passes. The other end of brush member is adjustable in the housing so that the angle of the brush member with respect to the workpiece or housing can be varied. Lock elements are provided to hold the brush member in its selected position.
In another embodiment, the brush members are arranged in a tubes. Each tube has a slot extending longitudinally at least along a part of its length. The tubes are rotatably arranged in the housing. The brush members extend through the slot with a first end of the brush arranged in the tube and a second end contacting the workpiece.
In a further embodiment of the present invention, the housing is attached to the plating chamber. Whether that chamber processes workpieces horizontally through any angle up to a vertical position, the housing containing the brush members is adjustable such that the brush members may be moved closer or farther from the plating chamber in a first direction, as well as in a second direction closer to or farther from the workpiece.